Novel 2D Silica Monolayers with Tetrahedral and Octahedral Configurations

TL;DR

This paper reports the discovery and characterization of two novel stable 2D silica monolayers with distinct tetrahedral and octahedral structures, highlighting their potential applications in nanotechnology and electronics.

Contribution

The study introduces two new stable 2D silica monolayers with unique structures and properties, supported by first principles calculations, and explores their potential applications.

Findings

O-silica is the strongest silica monolayer and acts as a dielectric substrate.

T-silica nanoribbons are metallic, while O-silica nanoribbons have band gaps.

Weak interaction between O-silica and graphene suggests potential for device integration.

Abstract

Free-standing and well-ordered two-dimensional (2D) silica monolayers with tetrahedral (T-silica) and octahedral (O-silica) building blocks are found to be stable by first principles calculations; T-silica is formed by corner-sharing SiO4 tetrahedrons in a rectangular network and O-silica consists of edge-sharing SiO6 octahedrons. Moreover, the insulating O-silica is the strongest silica monolayer, and can therefore act as a supporting substrate for nanostructures in sensing and catalytic applications. Nanoribbons of T-silica are metallic while those of O-silica have band gaps regardless of the chirality. We find the interaction of O-silica with graphene to be weak suggesting the possibility of its use as a monolayer dielectric material for graphene-based devices. Considering that the six-fold coordinated silica exists at high pressure in the bulk phase, the prediction of a small energy difference of O-silica with the synthesized silica bilayer together with the thermal stability at 1000 K suggest that synthesis of O-silica can be achieved in experiments.